Silicone elastomer golf ball core



Sept. 2, 1952 F. s. MARTIN 2,609,20l

SILICONE ELASTOMETER GOLF BALI. com:

Filed June 26, 1947 ATTORNEY Patented Sept. 2, 1952 UNITED STATES PATENTOFFICE v Y y 2,609,201 l t SILICONE ELASTOMER GOLF' BALL conn Frank S.Martin, Cranston, R. I., assgnor to United States Rubber Company, NewYork,

N. Y., a; corporation of New Jersey Application Jun-eac, 1947, serialNo. 757,145

The present i'nventionfrelates -to a novell golf ball core capable of'giving improved: golf ball performance.

For many years golf balls have been provided with a core of rubberforvother yielding material about which rubber thread was tightly wound toform the golf ball body, and over this body of thread was provided a`molded balata cover.

For a number of years golf balls havefbe'en provided with a liquidicenter such as paste, honey, oil or water confined within a rubber shellso that the center and shell form a core. One of the best golf balls'now on the market is a liquid center ball in' which. the core of theball contains a pellet-formed of aspherical thin plastic containerfilledwithv castor oil.l This pellet or center is disposed within arelatively thick shell of vulcanized resilient rubber?.M The' core thusformed has? rubberfthread wound tightly thereupon in a i highlyvstretched condition to forni the ball body, andthis body is disposed ina balata cover asY above described;`

Experienced golfersdesire the'l followingl properties in a ball:long'iiight, goodifeelionl the club when the ball is hit, good clicksound` when. the pball is hit and when itis dropped oniV ar-liardfsurface, long life without getting duti of shape, and a cover thatstands up welland` has a. goed white color of pleasing; appearance. Thecastor oil center ball above described when' made of high qualitycomponents possessesT alli of these properties toa substantial degree.

The present invention. relates* to* aiV golf". balllin' which the liquidcenterlof! the! core: justA described is replaced by.V airelativelyfnelw materialpossessing plastic' orfdoughyf properties so'that it can be workedV between theliin'gers'like.` putty, and whenrolled into alball. willtb'ounce to" ap#- proximately theV same degl-eelasia go'o'dl quality solid rubber ball. This strange material v'has'beenvgiven the. name2 of' bounbingl putty and will be hereinafterdescribed. greater detail.

Golf balls having a core'containinga center formed of this so-calledbouncing putty inplace or" the liquid -center above described, but whichare otherwise constructed like the liquid center balls are found togive'exc'ellent performance and to possess properties superior to othervhigh grade golf balls now on the market. Experienced golfe ers areparticularly pleased. with the click of this new ball and also with thefeel or property of the ball to get quickly ofi' of the club.

The various features of a golfvball having a core constructed inaccordance` with the present invention will be further understood from"the following description when ready in connection with theaccompanyingV drawing,y wherein:

Fig. 1 shows the major portion ofv a golfball constructed inaccordance-with thepresentinf vention Vin sections and a minor portionin side View; and

AFig. 2 illustrates the core alone of the ball of Fig. 1, the center ofthe core being shown in side view while the two' halves of the shell areshown in sectionand in spaced relation to each other. i A

The core of theV golf ball illustrated in the drawing is designated inits entirety-by the nu#Y meral Il). This corer comprises a center Ilformed oi a compound containing sufficient bouncing` putty to impartl totheV center pronounced bouncing properties and also putty-likeplasticity. The center Il is disposed within a relatively thick shell ofvulcanized natural rubber, synthetic rubber, or! resinous materialhaving elastic properties. The two halves ofthe shell designated. by l2Yand'` l2' inf Fig. 2 ofi the' drawing should bei vulcanized orcemented-toi gether` when iinislfiedtol flr-rrlly` unite them aboutthecenter Il.

After the core yIll" hasZ been constructed as' just described'rubberthread-is tightly wound about this core as' heretoforetoform abody l'3of the desired size. A cover i4 which may bef formed of balata is thenmolded aboutl the' bodyV inl a well known manner. and the Vcover ispainted and branded with the makers name or mark as heretofore.

The size and weight of golf balls have become st'ar'idardizedV andarefollowed carefully by golfball manufacturers. The diameter-ofthe -nishedball shouldj be 1168 inc'hesL The' other-T die mensions ofthe ball mayvary'wi'del-y" depending upon the type of ball to be made. A golf ballconstructed in accordance with the present invention and having a centerll about of an inch in diameterand` a core` I about 141% inches indiameter was' found t'o` perform ina very satisfactory manner. llher`body |31 of tightly wound rubber thread and cover' lllj having althickness of several hundredths of an inch were constructed asheretofore. v

The so-calledY bouncingv putty used in the cen'- ter Il` is preferablythe solid gel-like heat reac tion product ofV aV dimethyl silicone oil'with a minor portion of a compound of boron-such as pyroboric acid,boric anhydride or boric acid. This material has a specific gravity ofabout 1.03. It also' has pronounced cold flow properties in that al ballof this material will flow out into a thin disk in the course of' hours.It doesf not ow appreciably. underarapid-.blow butwillii'ow readilyunder the application of a low" steady pressure; it isalso stablethroughoutaverywde temperature range'. This bouncing! putty iiiay'beused aloney to. form the Vcenter Il;A or itmay be used-with pigments,lfillersor plasticizers ern-r ployedtoincreaseit-sweight ortoV modifyrits plastic properties lorvfor other reasons.

One important result secured byusing plastici-zers is that plasticizersreduceV the tendency of the bouncing putty to shatter under a rapidTable I Composition Treatment Test No milling or heatlng. Heated andmilled Shatter ed fairly easily.

Do. More diilicult to shatter. Do.

Do. Do.

o parts Bf P 100 B. P. and 100 zinc oxide.

100 B. P. and 10 zinc stearate.

100 B. P. and 10 Laurexl.

Composition of Table II given below.

do do l Laurex is a fatty acid activator and plasticizer and may bedescribed as a zinc salt of a mixture of fatty acids in which laurxcacid predominates.

The above compositions, Aexcept the rst, as indicated were heated tomelting during a .ten minute interval, stirred and then milled on arubber mill for ten minutes to complete the mixing. They were tested bystriking a small pellet, approximately A inch in diameter, a hard rapidblow with a hammer. Compositions 1 and 2 shattered fairly easily.vCompositions 3, 4, 5 and 6 were increasingly difficult to shatter inthe order they are listed. One composition containing the abovedescribed bouncing putty which is found to produce a very satisfactorycenter is the following, the parts being by weight:

Examples of the zinc soaps of fatty acids are:

1. zinc soaps of coconut oil fatty acids 2. zinc soap of lauric acid 3.zinc soap of stearic acid Golf ball cores having a diameter of lg inchesbut different centers all about of an inch in diameter were dropped froma height of 100 inches onto a hard surface to test their reboundproperties at a temperature of 80 F., with the following result. v

Table III Rebound, inches Core having center of 100% bouncing putty 67.8Core having center of compound of above Table II 65.5 Core having oilcapsule center 62.0

It is not entirely clear why a golf ball having a center formed ofbouncing putty but otherwise constructed as heretofore should perform insuch a satisfactory manner but professional golfers playing golf ballsconstructed in accordance with the present invention and unaware of thefact that it was? constructed differently from the balls they werefamiliar with have repeatedly commented upon the highly desirableproperties of this ball, as to click, feel and flight. They have alsocompared its playing properties with the castor oil center ball abovedescribed and lbelieve it to .have properties superior thereto.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. A golf ball core adapted to have rubber thread wound tightlythereupon to form the golf ball body; said core comprising a centerformed of a mixture of a solid gel-like heat reaction product of adimethyl silicone oil with a minor portion of a compound of'boron addedthereto and having pronounced bouncing properties that are equal tothose of good vulcanized elastic rubber and also having-puttyrlikeplasticity, said mixture also containing at least about 5% of zinc soapbased on the weight of said solid gel-like heat reaction product tosubstantially increase the shatter-resistant properties of the centerand containing an inorganic 1lerand a shell of vulcanized rubbersurrounding and coniining the center.

2. A golf ball core adapted to have rubber thread wound tightlythereupon to form the golf ball body; said core comprising a centerformed of a mixture of a solid gel-like heat reaction product of adimethyl silicone oil with a minor portion of a compound ofA boron addedthereto and having pronounced bouncing properties that are equal tothose of good 'vulcanized elastic rubber and also having putty-likeplasticity, said mixture also containing at least about 5% of zincstearate based on the Weight of said solid gel-like heat reactionproduct to substantially increase the shatter-resistant properties ofthe center and containing an inorganic filler, and a shell of vulcanizedrubber surrounding and conning the center. n

3. A golf ball core adapted to have rubber thread wound tightlythereupon to form the golf ball body; said core comprising a centerformed of a mixture of a'solid gel-like heat reaction product of adimethyl silicone oil with a minor portion of a compound' of boron addedthereto and having pronounced bouncing properties that are equal tothose of good vulcanized elastic rubber and also having putty-likeplasticity, said mixture also containing'at least about 5% of Zinclaurate based on the weight of said solid gel-like heat reaction productto substantially increase the shatter-resistant properties of the centerand containing an inorganic llenand a shell of vulcanized rubbersurrounding and confining the center.

FRANK S. MARTIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED sTATEs PATENTS OTHER REFERENCES The AmazingNew Chemical Family,pages 86-88, Oct. 6, 1945, The Oil and Gas Journal.

1. A GOLF BALL CORE ADAPTED TO HAVE RUBBER THREAD WOUND TIGHTLYTHEREUPON TO FORM THE GOLF BALL BODY; SAID CORE COMPRISING A CENTERFORMED OF A MIXTURE OF A SOLID GEL-LIKE HEAT REACTION PRODUCT OF ADIMETHYL SILICONE OIL WITH A MINOR PORTION OF A COMPOUND OF BORON ADDEDTHERETO AND HAVING PRONOUNCED BOUNCING PROPERTIES THAT ARE EQUAL TOTHOSE OF GOOD VULCANIZED ELASTIC RUBBER AND ALSO HAVING PUTTY-LIKEPLASTICITY, SAID MIX-